Schelle's 12mm Big Bore V2 Flat Screw Mount Shock Pistons were developed for Associated Big Bore V2 1/10 scale shocks that use 'screw on' type pistons. These pistons are precision machined and include Schelle's Shock Piston Tuning Guide. The Tuning Guide explains the handling characteristics of each piston going from the lowest damping (low resistance) to highest damping. These 2 x 1.7mm hole provide the least amount of damping in the Schelle Piston line, and are recommended for medium to low traction surfaces to deliver more grip when the car feels loose and when the track doesn't have large jumps.